Interest-computing and multiplying machine.



H. H. OLSEN.

INTEREST COMPUTING AND MULTIPLYING MACHINE.

APPLICATION FILED DEC. 7, I9I4 NNW HERMAN H. OLSEN, OF WHITEHALL,MICHIGAN. l

INTEREST-COMPUTING AND MULTIPLYING MACHINE.

Specification of Letters Patent.

Patented oet. 31, 1916.

Application led December 7, 1914. Serial No. 875,872.

To all whom t may concern:

Be it known that I, HERMAN H. OLsEN, a citizen of the United States ofAmerica, residing at Whitehall, in the county of Muskegon and State ofMichigan, have invented certain new and useful Improvements inInterest-Computing and Multiplyinfr Machines; and I do hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled iI the art to `which itappertains to make and use the same.

This invention relates to an interest computing and multiplying deviceby means of which the interest on any desired sum may be computed at anygiven rate or per cent., for any particular' length of time, the devicealso being adapted to be used in finding products resulting from themultiplication of. any selected multiplicand by any multip 1er.

Itis the object and purpose of this invention-to construct a device ofthis character by meansA of which these several computations may bequickly and easily made and the'result accurately determined, saidconstruction being of` very simple and economical design and veryreadily and easily operated. Y l

To these ends I have constructed the device shown in the accompanyingdrawing,

Figure 1 is a plan view of the device; Fig. 2 is a vertical sectiontaken transversely of said device; and'Fig. 3 is a view of a portion ofa computing sheet secured to one of the rolls used in the constructionof the device.

Like reference characters refer to likel .transparent material, isslidably mounted,

bein retained by clips d against accidental `disp acement. On theunderside of the plate a sheet of opaque material is fastened, saidsheet having a plurality of rows of openings e which are separated fromeach other by cut-off partitions g as shown, these rows being locatedlengthwise ofthe plate and with openings in one row directly below thosein the row next above.

'The rows `of openings are shown as vfour in number and immediatelybelow said openings are mounted four rolls having journals extendinginto and rotatably mounted in the ends I) of the casing, there beingprovided turn buttons i by means of which the rolls may be manuallyoperated. In the drawing said buttons are indicated at one end of thedevice but it is apparent they may be placed at either end or at bothends if desired. Each roll h has secured on the outer surface thereof asheet c which has printed thereon a plurality of numbers at one endindicating a principal on which, an interest is to be computed andthence in horizontal lines indicating the computed interest at the rateof v6% per annum for a plurality of numbers of days. 'In the presentconstruction said days are indicated in horizontal alinement in columnGranging from ten days to five hundred and forty days, as will beapparent from reference to Fig. 1. The uppermost roll may be known asthe thousands roll including all principals from one thousand to ninethousand, the second roll in similarV manner is the hundreds roll, the'third, the tens roll and the fourth, the units roll. It is of courseapparent that additional rolls may be used, for instance, tens ofthousands or hundreds of thousands ifneeded. The plate is slidablymounted in the casing and has secured thereto a tab lmiby means of whichit may be drawn manually to different positions. Secured also to theunderside of the plate c at the lower edge thereof, as shown in Fig. 1,is an opaque stripon which is printed a column of per cents. beginningat 1% and ending at 54%, this column being indicated at B. The principalon which the interest is to be computed will be read downward, thatshown in Fig. 1 being 2854 and the principal column is denoted byreference character A. It will, be noted also that on the basis of a 6%computation the vertical column under each multiple of will be the samemultiple of the principal indicated at the left hand side of the deviceas shown in Fig. 1 in the principal column A. For instance, in thevertical column under the number 180, disregarding the decimal point,will be found the figures, 6,000, 2400, 150 and 12, this being threetimes the numbers disclosed at the` left in Ycolumn A which are respecitively 2,000, 800, 50 and 4. In the same cipal is 44 divided by 6.

manner under the number 540 the multiple is 9 and under the number 420the multiple is 7; and if desired fractional multiples may be used asfor instance, under the number 80 the multiple will be 14, and so on.

Let it be supposed that the interest on $2,854.00 at 6% per annum for 65days is to be found. The operationl in such case is to turn the severalrolls so that the principal reading downward from the upper roll willappear as 2,000, 800, .50 and 4 on the four rolls. Under the numeral ofthe days column C we find respectively 20.00, 8.00, .50 and .04, the sumof which is the required interest on the said sum at 6% for 60 days, or$28.54. or the additional 5 days attention should then be directed tothe figures appearing under the number 50 in column C, the slide c beingmoved over to the left far enough that the cut-ofi' partition g will cutoff Athe last figure appearing' on each of the rolls under the numeral50. In this case such numbers are 1.67, .67, .04 and .00, the sum ofwhich added to $28.54 is $30.92 or the required interest. It will beclear `that by operating the slide 'c the interest for any requirednumber of days less than 10 may be obtained by merely cutting off' thelast kfigure of the numbers appearing under a number in column C whichis ten times the number of days desired.

The foregoing is the operation where the interest is at the rate of 6%per annum. Suppose however, it is desired to find the interest at adifferent rat-e forinstance, at 44% per annum. In this case it isnecessary to interpolate a new principal which at 6% per annum will havethe same interest computation as the given principal at 44%. Thisinterpolation is made in the following manner: Let the principal be62,854, the rate 44% and the time 100 days.

The first operation then is to pass to the per cent. column B to theposition occupied by 44% and it will be noted that above such position,disregarding the decimal point,

reading downward, are the figures 1500, 600, 37 and 3, the sum of whichis 2,140. These figures, it will be noted, bear the same ratio to thoseover the six per cent. character as does 44 to 6, and the interest onthe sum thereof at six per cent. accordingly, is the same as theinterest 0n 2,854 at four and onehalf per cent. for any given time. Oras will later appear, the multiplier byv which 2854 is multiplied toobtain the new prin- This is the new principal which should be used inplace of $2,854,

l the rolls being operated so that 2,000 shall appear on the thousandsroll, one hundred on the hundreds roll, 40 on the tens roll, with nofiguresshowing on the units roll. Then by passing over to the figuresappearf ing under 100 days will be found the interest on the sums2,000,100 and 40 which added together will give the interest for 100 days at44% on $2,854. The saine operation may lie-gone through with todetermine the interest at any other desired rate for any other number ofdays. I have used a certain principal, namely $2,854, merely as a matterof examplebut any principal from $1.00 to $9,999.00 may be used.

It is of course apparent that the interpolated principal may at sometimes be more than 9,999. For example suppose that it should be 23,421.With four rolls only as in the device shown, it would be necessary touse the first four figures of this sum or 2,342 as the principalobtaining the interest on this sum at the desired rate for the requirednumber of days and multiplying it by 10 and afterward adding theinterest on the $1.00 additional at the given rate for the requirednumber of days. Of course as heretofore noted the mechanism is notlimited to the four rolls but may have additional rolls if desired, totake care of such contingencies.

Thefollowing illustration will show how the device may be used in theprocess of multiplying. The multiplicand is 2,854 which is to bemultiplied by 623. For this multiplication the first operation is topass to the numeral180 which is three times 60 in column C and add upthe figures appearing underneath, disregarding the decimal point, thesum ,of which will be 8,562 which may be marked down in any convenientmanner. This multiplies the selected multiplicand by the units digit 3.To multiply by 2 the tens digit the figures under the 120 numeral whichis two times 60 are added together amounting to 5,708 to which an 0 isadded making 57,080 by reason of the fact that the multiplicand is beingmultiplied by 20 instead of- 2l as in 623 the 2 occupies tens place; andfinally to multiply by the 6 the figures under the 360 day numeral whichisy six times 60 are added together amounting to 17,124 to which two 00sare added as the 6 is in. hundreds place making 1,712,400, then byadding together 8,562, 57,080 and 1,712,400 the vproduct will beobtained being 1,778,042. In the saine way multiplication by any of thefractional multipliers shown in the column indicated asr Multipliercolumn may be had to determine the product of any selected multiplicandby said fractional multiplier.

Various changes in minor detail of construction may be resorted towithout departing from my invention which is adapted to be used in themanners indicated and in other ways not specifically described.` Theclaims define the invention and all modifications falling within theirscope are to be considered as comprehended withinl the invention.

1. In a device of the character described, a casing, a closure mountedat the upper side thereof and having a plurality of rows of transparentsections therein, a roll rota-` tably mounted below each row oftransparent sections, each roll having thereon a plurality of rows ofcomputations of interest on a pluraiityof principals for different timesat a given rate, saldv computations being adapted to show through thetransparent sections of the closure, a column having represented thereinthe numbers of days for the said computations located at one side of thecasing and with said numbers in operative alinement with thecomputations corresponding thereto and a .column at the opposite side ofthe casing secured to the slide containing a plurality of per cents.,

each being one tenth of the respective number of days in the days columndirectly opposite at the opposite side of the casing.

In a device of the character described, a casing, a closure mounted atthe upper side thereof and having a plurality of rows of transparentsections therein, a roll rotatably mounted below each roW of transparentsections, each roll having thereon a plurality of rows of computationsof interest on a vplurality of principals for different times at a givenrate, said computations being adapted to show through the transparentsections of the closure, and a column having represented therein thenumbers of days for the said computations located at one side of thecasing and with, said numbers in operative alinement with thecomputations corresponding thereto, and a second column similai-1ylocated at; the vopposite side of the casing denoting a plurality of percents., each per cent. being one tenth of the corresponding numbers of,days in the first column. Y

In testlmony whereof I affix my signature 1n presence of two Witnesses.y

HERMAN H. oLs'EN.

Witnesses c ALBERT MICKELSON, J oHN HAVERKATE.

